Bogies which are most commonly found in current use and are not articulated, consist of a rigid chassis made up by two side frames and at least one cross member, and are in no condition to absorb anything more than a slight error in level, using their suspension systems. The rigidity of the frame prevents the vertical twisting deformations which would be needed to maintain the same amount of loading on all the wheels. Some wheels can consequently be in a position where they are not subject to loading, which may bring about a derailment. Obviously this risk increases under certain operating conditions.
Various types of articulated bogies are already known, which do allow a certain degree of deformation of their frame, but these suffer from numerous disadvantages, due to the complexity of their design; this results in high cost, both as regards their manufacture and their maintenance during operation.
The present invention provides a novel solution, which is simpler and more economical, for the provision of an articulated bogie.